This is a prososal to investigate the possibility that amphetamine injected directly in brain tissue can be a reinforcing stimulus. Our pilot work has shown that injections of amphetamine in a part of the spetal region not only augment electrical self-stimulation but also support direct self-administration. Three series of experiments are designed to answer three central questions about the discriminative properties of amphetamine self-injected into the brain: (1) Is it a reinforcing stimulus that will support response aquisition, response reversal and frustration responding in extinction? (2) Is it a remembered stimulus that will produce spontaneous recovery, priming, and fixed ratio responding? (3) Is it a self-regulated stimulus that will be maintained at a constant level, even when some shots are delivered automatically or by a yoked control animal? Intracerebral self-injection (ICSI) will also be tested in combination with intravenous injection to see if they enhance one another or substitute for one another. The entire experimental series will also be conducted with cocaine after we have the answers for amphetamine. We will also study the interactions between norepinephrine and opiods in the control of feeding, self-stimulation and self-injection.